Question: I have to come up with unique ID for each networked client, such that:
A little bit of explanation and some back-story:
This question is basically age old question that also touches the topic of software copy-protection, as some of the mechanisms used in that area are mentioned here. I should be clear at this point that I'm not looking for a copy-protection scheme. Please, read on. :)
I'm working on a client-server software that is supposed to work in a local network. One of the problems I have to solve is to identify each unique client in the network (not so much of a problem), so that I can apply certain attributes to every specific client, retain and enforce those attributes during the deployment lifetime of a specific client.
While I was looking for a solution, I was aware of the following:
The obvious choice for this kind of problem would be to find out BIOS identifiers (not 100% sure if this is unique through identical motherboard models, though), as that's the only thing I can rely on that isn't duplicated, transferred by cloning, and that can't be changed (at least not by using some user-space program). Everything else fails as either being not reliable (MAC cloning, anyone?), or too demanding (in terms that it's too sensitive to configuration changes).
Sub-question that I'd like to ask is, am I doing it correctly, architecture-wise? Perhaps there is a better tool for the task that I have to accomplish...
Another approach I had in mind is something similar to a handshake mechanism, where a server maintains an internal lookup table of connected client IDs (which can be even completely software-based and non-unique at any given moment), and tells the client to come up with a different ID during handshake, if a duplicate ID is provided upon connection. That approach, unfortunately, doesn't play nicely with one of the requirements to tie attributes to specific client during lifetime.
What you're looking for is the Windows WMI. You can get the motherboard ID (which is unique across the same type of motherboard) or many many other types of unique identifiers and come up with some clever seeded function to generate a UHID. Whoa did I just make up an acronym?
And if you're looking specifically for getting the Motherboard (BIOS) ID:
WMI class: Win32_BIOS
Namespace: \Root\Cimv2
Documentation: http://msdn.microsoft.com/en-us/library/aa394077(VS.85).aspx
Sample code: http://msdn.microsoft.com/en-us/library/aa390423%28VS.85%29.aspx
Edit: You didn't specify a language (and I assumed C++), but this can be done in Java (with a COM driver), and any .NET language, as well.